<p>Radiosity and other global illumination methods for image synthesis calculate the real world radiance values of a scene instead of the display radiance values that will represent them. Though radiosity and ray tracing methods can compute extremely accurate and wide-ranging scene radiances, modern display devices emit light only in a tiny fixed range. The radiances must be converted, but ad-hoc conversions cause serious errors and give little assurance that the evoked visual sensations are truly equivalent. Sensation-preserving conversions for display, already known in photography, printing, and television as tone reproduction methods, are discussed. Computer graphics workers can apply the existing photographic methods, but may also extend them to include more complex and subtle effects of human vision using the published findings of vision researchers. Ways of constructing a sensation-preserving display converter, or tone reproduction operator, for monochrome images are demonstrated.</p>